Corrosion of metals can be a significant problem where metal surfaces are exposed to water, air, inorganic metal salts, and the like. One very significant source of corrosion is a seawater environment, that is, seawater itself, seawater mist or spray, or the salty air which can exist near bodies of seawater. A seawater environment can attack and corrode ferrous and non-ferrous metals. A variety of equipment is subject to corrosion by seawater, including piping, dry-docks, steel cables, superstructures of and equipment on offshore drilling and production rigs, desalination plants, seawater mineral extracting plants, surfaces of ships and barges, and tanks subjected to seawater environment.
Many corrosion preventive compositions are known. One is disclosed in U.S. Pat. No. 3,925,087 issued Dec. 9, 1975, to Lechner et al. The composition disclosed in U.S. Pat. No. 3,925,087 generally provides a coating of no greater than 3 mils, or more typically, 1 to 2 mils. In general, a thicker coating will last longer and provide better corrosion resistance than a thinner coating of an equally effective substance. However, when applied in a thicker layer, this type of coating requires an inconveniently long period of time to cure. In addition, a thicker layer tends to flow, and a coating thickness of greater than about 3 or 4 mils generally cannot be maintained. Further, while the compositions of Lechner can inhibit corrosion for an adequate period of time, longer-lasting corrosion protection is highly desirable.
Accordingly, a need exists for a corrosion or rust preventive coating composition which will maintain a coating thickness of greater than 3 mils, which will cure rapidly and which will exhibit exceptionally effective and long lasting corrosion prevention.